The surprise decision by US trade representative Jamieson Greer to impose fees on car carriers built anywhere outside the US has raised the spectre of litigation over the move.

Greer, the chief trade ambassador for US President Donald Trump, announced on Thursday that car carriers will pay a fee of $150 per ceu starting in 180 days.

The fee emerged among a series of fees that followed an investigation into Chinese maritime dominance, but it would also apply to other shipbuilding nations, like major car carrier builders Japan and South Korea.